N, P co-doped graphene enriched phosphorus as a highly efficient oxygen reduction catalyst

Abstract

• N -doped first to promote the introduction of P into Gr at secondary heat treatment. • While doping N, high content P doping with 2.61 at% is realized in P N Gr. • P N Gr shows high specific surface area and abundant micro- and mesopores. • P N Gr displays excellent ORR and alkaline zinc-air battery discharge performance. • P N Gr exhibits wonderful stability and methanol resistance. Heteroatoms doped metal-free carbon catalysts are considered as promising alternatives to commercial Pt/C for oxygen reduction reaction (ORR). Here, we report a phosphorus-enriched nitrogen and phosphorus co-doped graphene catalyst (P N Gr) via a facile and economical two-step pyrolysis approach. Thanks to its outstanding properties, such as unique honeycomb-like morphology, high Brunauer-Emmett-Teller (BET) surface area (935 m 2 /g), and abundant of phosphorus content (2.61 at%), the obtained P N Gr exhibits a high ORR activity with a half-wave potential of 0.82 V and a limiting current density of −5.98 mA cm −2 in alkaline electrolyte solution. Notably, the zinc-air battery assembled with P N Gr as cathode catalyst also shows an excellent discharge performance and stability.